This is a cast iron hitching weight. Back when horses were used for transportation there would be times when no way to tie up a horse a heavy weight was carried in the wagon. This one belonged to Ben Varga a San Antonio saddle and boot maker. It was cast by Alamo Iron works San Antonio probably in the early 1900's late 1890's marked with an A X on the underside.
I found it at a scrap yard, where at that time one was allowed to rummage thru the piles of metal and purchase it by weight.
It is no longer exists.